The Experts below are selected from a list of 243 Experts worldwide ranked by ideXlab platform

Roberto Verdone - One of the best experts on this subject based on the ideXlab platform.

  • RTSI - Joint routing and scheduling for centralised wireless sensor networks
    2016 IEEE 2nd International Forum on Research and Technologies for Society and Industry Leveraging a better tomorrow (RTSI), 2016
    Co-Authors: Chiara Buratti, Roberto Verdone
    Abstract:

    We consider a centralised wireless sensor network, where nodes have to send data to a Final Sink, managing both routing and radio resources assignment. We propose two novel algorithms to jointly assign time slots to links and to define paths connecting nodes to the Sink. In contrast with previous works, the proposed algorithms account for a realistic capture effect, where the signal-to-interference-ratio considering the sum of interfering powers is applied. The proposed algorithms, taking inspiration from Dijkstra and graph coloring techniques, are compared to two benchmarks considering a simulated and a real network. It is shown that the proposed algorithms can assign a smaller amount of radio resources with respect to benchmarks, or ensure error-less transmissions in the network.

  • Joint routing and scheduling for centralised wireless sensor networks
    2016 IEEE 2nd International Forum on Research and Technologies for Society and Industry Leveraging a better tomorrow (RTSI), 2016
    Co-Authors: Chiara Buratti, Roberto Verdone
    Abstract:

    We consider a centralised wireless sensor network, where nodes have to send data to a Final Sink, managing both routing and radio resources assignment. We propose two novel algorithms to jointly assign time slots to links and to define paths connecting nodes to the Sink. In contrast with previous works, the proposed algorithms account for a realistic capture effect, where the signal-to-interference-ratio considering the sum of interfering powers is applied. The proposed algorithms, taking inspiration from Dijkstra and graph coloring techniques, are compared to two benchmarks considering a simulated and a real network. It is shown that the proposed algorithms can assign a smaller amount of radio resources with respect to benchmarks, or ensure error-less transmissions in the network.

  • performance analysis of ieee 802 15 4 non beacon enabled mode
    IEEE Transactions on Vehicular Technology, 2009
    Co-Authors: Chiara Buratti, Roberto Verdone
    Abstract:

    In this paper, an analytical model for the non beacon-enabled mode of the IEEE 802.15.4 medium access control (MAC) protocol is provided. A wireless sensor network (WSN) composed of nodes, which transmit data to a Sink through direct links, is considered. Upon reception of a query from the Sink, the nodes transmit their packets by using the carrier-sense multiple access with collision-avoidance algorithm defined by IEEE 802.15.4. Our mathematical model allows the evaluation of the statistical distribution of the traffic generated by the nodes. In particular, the probability that a node succeeds when accessing the channel, and that the Final Sink receives a packet coming from whatever node, is derived. The results show how the distribution of traffic changes when different loads are offered to the network. Moreover, the model allows the evaluation of the optimum size a packet should have so that the success probability for its transmission is maximized. The results are validated through simulations. The model differs from those previously published by other authors in the literature as it precisely follows the MAC procedure defined by the standard in the context of the WSN scenario described.

W. Ahlf - One of the best experts on this subject based on the ideXlab platform.

  • Entwicklung von ökotoxikologischen Instrumenten und ihre rechtliche Implementierung zur marinen ökologischen Risikobewertung von Chemikalien, Pestiziden und Baggergut
    Environmental Sciences Europe, 2009
    Co-Authors: C. Floeter, H. t. Ratte, W. Ahlf
    Abstract:

    Background, aim, and scope The marine environment is often the Final Sink for pollutants, especially for persistent organic pollutants (POPs) and for persistent, bioaccumulative and toxic (PBT) substances. The body burden of marine top predators in the Baltic Sea, in the North Sea and also in the Arctic seas is alarming. Thus, the question was investigated if the European environmental law considers a prospective marine ecological risk assessment of chemicals, pesticides and dredged material before they are launched on the market or disposed to the sea. Results The analysis of European environmental law showed that the European environmental protection goals demand a good quality status of coastal waters until 2015 (Waterframework Directive) and a good quality status of European seas until 2020 (Marine Strategy Directive), but a specific marine ecological risk assessment of chemicals and pesticides is not sufficiently required in current European legislation. Discussion It was shown that the ecological risk assessment for freshwater ecosystems is, due to the pecularities of pollutant impacts in the marine environment, not adequate to predict marine effects and to protect the marine environment sufficiently. A statistical analysis of international databases on the relative toxicity of narcotics revealed that marine organisms can be significantly more sensitive than freshwater organisms towards substances with an unspecific mode of action (narcotics). Approximately 60 % of the industrial chemicals are classified as narcotics by their mode of action. Thus, this substance class is of environmental importance. Due to the hydrophobic properties and the low solubility of narcotics in seawater, the ecotoxicological assessment of marine sediments was of interest. An estuarine and marine bioassay test set was established and further developed to assess the ecotoxicological potential of brackish and seawater sediments. It was important that the test procedures were adapted to brackish and marine conditions and were harmonised between each other as well as on the international level. Conclusions Beside two bioassays for the ecotoxicological assessment of elutriates of marine and brackish sediments (bacteria bioluminescence test and marine algae test), the implementation and further development of the whole sediment bioassay with the marine amphipod Corophium volutator was important for enhancing the risk assessment. In order to gain a more standardised, all-season available test organism, the marine amphipod was for the first time reproduced under laboratory conditions the whole year round (also in winter), which is the essential basis for the urgently needed chronic whole sediment bioassay. The results of this investigation were implemented in the international (ISO), European (EN) and national (DIN) standardisations. Therefore, a standardised test set is ready for the implementation in the marine ecological risk assessment of chemicals, pesticides and dredged material in international, European and national legislation. Recommendations and perspectives Recommendations to improve the implementation of a marine risk assessment in European regulations are given with the goal to reach the internationally required objective of a sustainable development of the seas. Hintergrund und Ziel Die marine Umwelt ist oftmals die Finale Senke für Schadstoffe, insbesondere für persistente, bioakkumulative und toxische Schadstoffe (PBT Substanzen). Die Schadstoff-Belastung von marinen Top-Prädatoren ist in der Nord- und Ostsee und aufgrund des Schadstoffferntransportes sogar auch in der Arktis besorgniserregend. Folglich war zu prüfen, ob das europäische Umweltrecht bei der prospektiven Risikobewertung von Chemikalien, Pestiziden und Baggergut auch die marine Umwelt in Form einer gesonderten marinen ökologischen Risikobewertung berücksichtigt. Resultate Die juristische Analyse des europäischen Umweltrechts zeigte, dass die europäischen Schutzzielbestimmungen eine gute Qualität von Küstengewässern bis 2015 (EU-Wasserrahmenrichtlinie) und einen guten Qualitätszustand der europäischen Meere bis 2020 (Meeresstrategie-Rahmenrichtlinie) vorsehen, aber eine prospektive ökologische Risikobewertung von Chemikalien und Pestiziden für Meerwasserökosysteme insgesamt nur unzureichend im europäischen Umweltrecht verankert ist. Diskussion Es wurde dargelegt, dass eine alleinige Risikobewertung für Süßwasserökosysteme aufgrund der Besonderheiten der Schadstoffwirkung in der marinen Umwelt für einen umfassenden Schutz der Meeresumwelt nicht ausreicht. Eine statistische Auswertung internationaler Datenbanken zur relativen Toxizität von Narkotika gab einen Hinweis darauf, dass marine Organismen gegenüber Substanzen mit einem unspezifischen Wirkmechanismus signifikant sensitiver als ihre Süßwasservertreter sein können. Ca. 60 % der Industriechemikalien werden nach ihrem Mode of Action (MoA) als Narkotika klassifiziert und sind somit für die Umwelt von großer Bedeutung. Aufgrund ihrer hydrophoben Eigenschaften und ihrer geringeren Löslichkeit im Meerwasser war insbesondere die ökotoxikologische Risikobewertung von marinen Sedimenten von Bedeutung. Es wurde ein marines Biotest-Set aufgebaut und weiterentwickelt, um das ökotoxikologische Potenzial von Schadstoffen in aestuarinen und marinen Sedimenten zu erfassen. Ein Test-Set bestehend aus drei Biotestverfahren wurde auf die Besonderheiten unter Meerwasserbedingungen angepasst, sowie untereinander und im internationalen Vergleich harmonisiert und validiert. Schlussfolgerungen Neben zwei Testverfahren für die Bewertung des wässrigen Eluats mariner Sedimente (Leuchtbakterientest und mariner Algentest) war vor allem auch die Etablierung und Weiterentwicklung eines Gesamtsedimenttests mit dem Amphipoden Corophium volutator für die Risikobewertung von aestuarinen und marinen Sedimenten wichtig. Um einen das ganze Jahr verfügbaren, standardisierteren Testorganismus zu erhalten, wurde Corophium volutator erstmals zu allen Jahreszeiten unter Laborbedingungen zur Reproduktion gebracht. Die Reproduktionsergebnisse stellen eine essenzielle Basis für den international dringend geforderten chronischen Gesamtsedimenttest dar. Die Forschungsergebnisse sind direkt in die internationale (ISO), europäische (EN) und nationale (DIN) Standardisierung gemündet, so dass jetzt drei standardisierte und validierte Testverfahren für die Bewertung mariner Sedimente und zur Risikobewertung von Chemikalien und Pestiziden zur Verfügung stehen. Empfehlungen und Perspektiven Es wurde ferner aufgezeigt, wie eine marine ökologische Risikobewertung im europäischen Umweltrecht vollzogen werden müsste, um den international formulierten Schutzzielbestimmungen eines nachhaltigen Meeresumweltschutzes gerecht zu werden.

Chiara Buratti - One of the best experts on this subject based on the ideXlab platform.

  • RTSI - Joint routing and scheduling for centralised wireless sensor networks
    2016 IEEE 2nd International Forum on Research and Technologies for Society and Industry Leveraging a better tomorrow (RTSI), 2016
    Co-Authors: Chiara Buratti, Roberto Verdone
    Abstract:

    We consider a centralised wireless sensor network, where nodes have to send data to a Final Sink, managing both routing and radio resources assignment. We propose two novel algorithms to jointly assign time slots to links and to define paths connecting nodes to the Sink. In contrast with previous works, the proposed algorithms account for a realistic capture effect, where the signal-to-interference-ratio considering the sum of interfering powers is applied. The proposed algorithms, taking inspiration from Dijkstra and graph coloring techniques, are compared to two benchmarks considering a simulated and a real network. It is shown that the proposed algorithms can assign a smaller amount of radio resources with respect to benchmarks, or ensure error-less transmissions in the network.

  • Joint routing and scheduling for centralised wireless sensor networks
    2016 IEEE 2nd International Forum on Research and Technologies for Society and Industry Leveraging a better tomorrow (RTSI), 2016
    Co-Authors: Chiara Buratti, Roberto Verdone
    Abstract:

    We consider a centralised wireless sensor network, where nodes have to send data to a Final Sink, managing both routing and radio resources assignment. We propose two novel algorithms to jointly assign time slots to links and to define paths connecting nodes to the Sink. In contrast with previous works, the proposed algorithms account for a realistic capture effect, where the signal-to-interference-ratio considering the sum of interfering powers is applied. The proposed algorithms, taking inspiration from Dijkstra and graph coloring techniques, are compared to two benchmarks considering a simulated and a real network. It is shown that the proposed algorithms can assign a smaller amount of radio resources with respect to benchmarks, or ensure error-less transmissions in the network.

  • performance analysis of ieee 802 15 4 non beacon enabled mode
    IEEE Transactions on Vehicular Technology, 2009
    Co-Authors: Chiara Buratti, Roberto Verdone
    Abstract:

    In this paper, an analytical model for the non beacon-enabled mode of the IEEE 802.15.4 medium access control (MAC) protocol is provided. A wireless sensor network (WSN) composed of nodes, which transmit data to a Sink through direct links, is considered. Upon reception of a query from the Sink, the nodes transmit their packets by using the carrier-sense multiple access with collision-avoidance algorithm defined by IEEE 802.15.4. Our mathematical model allows the evaluation of the statistical distribution of the traffic generated by the nodes. In particular, the probability that a node succeeds when accessing the channel, and that the Final Sink receives a packet coming from whatever node, is derived. The results show how the distribution of traffic changes when different loads are offered to the network. Moreover, the model allows the evaluation of the optimum size a packet should have so that the success probability for its transmission is maximized. The results are validated through simulations. The model differs from those previously published by other authors in the literature as it precisely follows the MAC procedure defined by the standard in the context of the WSN scenario described.

C. Floeter - One of the best experts on this subject based on the ideXlab platform.

  • Entwicklung von ökotoxikologischen Instrumenten und ihre rechtliche Implementierung zur marinen ökologischen Risikobewertung von Chemikalien, Pestiziden und Baggergut
    Environmental Sciences Europe, 2009
    Co-Authors: C. Floeter, H. t. Ratte, W. Ahlf
    Abstract:

    Background, aim, and scope The marine environment is often the Final Sink for pollutants, especially for persistent organic pollutants (POPs) and for persistent, bioaccumulative and toxic (PBT) substances. The body burden of marine top predators in the Baltic Sea, in the North Sea and also in the Arctic seas is alarming. Thus, the question was investigated if the European environmental law considers a prospective marine ecological risk assessment of chemicals, pesticides and dredged material before they are launched on the market or disposed to the sea. Results The analysis of European environmental law showed that the European environmental protection goals demand a good quality status of coastal waters until 2015 (Waterframework Directive) and a good quality status of European seas until 2020 (Marine Strategy Directive), but a specific marine ecological risk assessment of chemicals and pesticides is not sufficiently required in current European legislation. Discussion It was shown that the ecological risk assessment for freshwater ecosystems is, due to the pecularities of pollutant impacts in the marine environment, not adequate to predict marine effects and to protect the marine environment sufficiently. A statistical analysis of international databases on the relative toxicity of narcotics revealed that marine organisms can be significantly more sensitive than freshwater organisms towards substances with an unspecific mode of action (narcotics). Approximately 60 % of the industrial chemicals are classified as narcotics by their mode of action. Thus, this substance class is of environmental importance. Due to the hydrophobic properties and the low solubility of narcotics in seawater, the ecotoxicological assessment of marine sediments was of interest. An estuarine and marine bioassay test set was established and further developed to assess the ecotoxicological potential of brackish and seawater sediments. It was important that the test procedures were adapted to brackish and marine conditions and were harmonised between each other as well as on the international level. Conclusions Beside two bioassays for the ecotoxicological assessment of elutriates of marine and brackish sediments (bacteria bioluminescence test and marine algae test), the implementation and further development of the whole sediment bioassay with the marine amphipod Corophium volutator was important for enhancing the risk assessment. In order to gain a more standardised, all-season available test organism, the marine amphipod was for the first time reproduced under laboratory conditions the whole year round (also in winter), which is the essential basis for the urgently needed chronic whole sediment bioassay. The results of this investigation were implemented in the international (ISO), European (EN) and national (DIN) standardisations. Therefore, a standardised test set is ready for the implementation in the marine ecological risk assessment of chemicals, pesticides and dredged material in international, European and national legislation. Recommendations and perspectives Recommendations to improve the implementation of a marine risk assessment in European regulations are given with the goal to reach the internationally required objective of a sustainable development of the seas. Hintergrund und Ziel Die marine Umwelt ist oftmals die Finale Senke für Schadstoffe, insbesondere für persistente, bioakkumulative und toxische Schadstoffe (PBT Substanzen). Die Schadstoff-Belastung von marinen Top-Prädatoren ist in der Nord- und Ostsee und aufgrund des Schadstoffferntransportes sogar auch in der Arktis besorgniserregend. Folglich war zu prüfen, ob das europäische Umweltrecht bei der prospektiven Risikobewertung von Chemikalien, Pestiziden und Baggergut auch die marine Umwelt in Form einer gesonderten marinen ökologischen Risikobewertung berücksichtigt. Resultate Die juristische Analyse des europäischen Umweltrechts zeigte, dass die europäischen Schutzzielbestimmungen eine gute Qualität von Küstengewässern bis 2015 (EU-Wasserrahmenrichtlinie) und einen guten Qualitätszustand der europäischen Meere bis 2020 (Meeresstrategie-Rahmenrichtlinie) vorsehen, aber eine prospektive ökologische Risikobewertung von Chemikalien und Pestiziden für Meerwasserökosysteme insgesamt nur unzureichend im europäischen Umweltrecht verankert ist. Diskussion Es wurde dargelegt, dass eine alleinige Risikobewertung für Süßwasserökosysteme aufgrund der Besonderheiten der Schadstoffwirkung in der marinen Umwelt für einen umfassenden Schutz der Meeresumwelt nicht ausreicht. Eine statistische Auswertung internationaler Datenbanken zur relativen Toxizität von Narkotika gab einen Hinweis darauf, dass marine Organismen gegenüber Substanzen mit einem unspezifischen Wirkmechanismus signifikant sensitiver als ihre Süßwasservertreter sein können. Ca. 60 % der Industriechemikalien werden nach ihrem Mode of Action (MoA) als Narkotika klassifiziert und sind somit für die Umwelt von großer Bedeutung. Aufgrund ihrer hydrophoben Eigenschaften und ihrer geringeren Löslichkeit im Meerwasser war insbesondere die ökotoxikologische Risikobewertung von marinen Sedimenten von Bedeutung. Es wurde ein marines Biotest-Set aufgebaut und weiterentwickelt, um das ökotoxikologische Potenzial von Schadstoffen in aestuarinen und marinen Sedimenten zu erfassen. Ein Test-Set bestehend aus drei Biotestverfahren wurde auf die Besonderheiten unter Meerwasserbedingungen angepasst, sowie untereinander und im internationalen Vergleich harmonisiert und validiert. Schlussfolgerungen Neben zwei Testverfahren für die Bewertung des wässrigen Eluats mariner Sedimente (Leuchtbakterientest und mariner Algentest) war vor allem auch die Etablierung und Weiterentwicklung eines Gesamtsedimenttests mit dem Amphipoden Corophium volutator für die Risikobewertung von aestuarinen und marinen Sedimenten wichtig. Um einen das ganze Jahr verfügbaren, standardisierteren Testorganismus zu erhalten, wurde Corophium volutator erstmals zu allen Jahreszeiten unter Laborbedingungen zur Reproduktion gebracht. Die Reproduktionsergebnisse stellen eine essenzielle Basis für den international dringend geforderten chronischen Gesamtsedimenttest dar. Die Forschungsergebnisse sind direkt in die internationale (ISO), europäische (EN) und nationale (DIN) Standardisierung gemündet, so dass jetzt drei standardisierte und validierte Testverfahren für die Bewertung mariner Sedimente und zur Risikobewertung von Chemikalien und Pestiziden zur Verfügung stehen. Empfehlungen und Perspektiven Es wurde ferner aufgezeigt, wie eine marine ökologische Risikobewertung im europäischen Umweltrecht vollzogen werden müsste, um den international formulierten Schutzzielbestimmungen eines nachhaltigen Meeresumweltschutzes gerecht zu werden.

Mathias Bochow - One of the best experts on this subject based on the ideXlab platform.

  • WHISPERS - Spectral Modeling of Plastic Litter in Terrestrial Environments - Use of 3D Hyperspectral Ray Tracing Models to Analyze the Spectral Influence of Different Natural Ground Surfaces on Remote Sensing Based Plastic Mapping
    2019 10th Workshop on Hyperspectral Imaging and Signal Processing: Evolution in Remote Sensing (WHISPERS), 2019
    Co-Authors: Theres Kuester, Mathias Bochow
    Abstract:

    Plastics have become an indispensable part of our daily life. It is a group of materials with outstanding properties for various products in a wide range of applications. They are durable, lightweight and cost-effective to manufacture. However, these advantages can develop to disadvantages if plastics are released into the environment uncontrolled and in large quantities. Here, both seas and soils form a Final Sink. Remote sensing has been used for many decades to observe the earth’s surface and the processes that take place on it. The detection and identification of plastic litter is one of the latest applications of remote sensing. In recent publications, the potential of imaging spectroscopy has been highlighted, since it allows material identification and quantification based on material-specific absorption bands. In this study we investigate the influence of the object transparency and background surface reflectance on the detection and identification using hyperspectral remote sensing.

  • Spectral Modeling of Plastic Litter in Terrestrial Environments - Use of 3D Hyperspectral Ray Tracing Models to Analyze the Spectral Influence of Different Natural Ground Surfaces on Remote Sensing Based Plastic Mapping
    2019 10th Workshop on Hyperspectral Imaging and Signal Processing: Evolution in Remote Sensing (WHISPERS), 2019
    Co-Authors: Theres Kuester, Mathias Bochow
    Abstract:

    Plastics have become an indispensable part of our daily life. It is a group of materials with outstanding properties for various products in a wide range of applications. They are durable, lightweight and cost-effective to manufacture. However, these advantages can develop to disadvantages if plastics are released into the environment uncontrolled and in large quantities. Here, both seas and soils form a Final Sink. Remote sensing has been used for many decades to observe the earth's surface and the processes that take place on it. The detection and identification of plastic litter is one of the latest applications of remote sensing. In recent publications, the potential of imaging spectroscopy has been highlighted, since it allows material identification and quantification based on material-specific absorption bands. In this study we investigate the influence of the object transparency and background surface reflectance on the detection and identification using hyperspectral remote sensing.